Many people throughout the world keep domesticated animals as pets within their homes. Many times these animals have only limited access to spaces outside the home or are otherwise unable to readily access an outdoor location for excreting waste materials on a regular basis. Consequently, it is necessary for the homeowners to make provisions which allow the animal to eliminate excretion products inside the home.
The most typical type of facility for cats or other small pet animals is a litter box. In its simplest and most common form, a litter box is formed from a relatively inexpensive open-sided container filled with commercially purchased litter material. The box, which may be an open-sided corrugated cardboard box, has a floor with four vertically upstanding side walls, which side walls function to contain the litter material within the box. The litter material is generally an unconsolidated granular mixture. Various types of natural and synthetic materials, both organic and inorganic, have been used in the past for litter materials.
In the past, it has been necessary to replace the litter in such litter boxes on a frequent and regular basis. Since the prior art litter has generally been disposable, the relatively high cost of commercially available litter has produced economic pressure to delay changing of the litter material as long as practically possible. Toward this end, the manufacturers of prior art litter materials have sought to make them absorbent, odor masking and bacteriostatic. Nevertheless, if the cat or other pet animal uses the litter on a regular basis, replacement of the litter material is required at least on a weekly basis.
In addition to the relatively high cost of continually replacing the litter material, disposal of the used litter is generally viewed as an unsanitary and undesirable task. In fact, for many persons, the undesirability of disposing of used litter represents a more serious disadvantage than the cost of replacement litter.
There have been several attempts in the prior art to eliminate the expense and unpleasantness of changing animal litter. For the most part, these efforts have been directed toward the composition of the litter material itself. However, no material has ever been developed which completely absorbs animal excretions or which renders such excretions odorless or sanitary. While attempts have been made to remove animal excretions, most of these attempts have been directed toward large-scale commercial ventures and have not proved practical in a home environment. Those devices which have been designed for small-scale home use have, for the most part, had other practical problems. For example, in U.S. Pat. No. 2,204,416 to Kramer an animal toilet is provided which automatically flushes in response to the movement of an animal from the excretion area.